Effects of corticotropin releasing hormone on human brain function: an analysis based on auditory evoked potentials

There is evidence that the peptides derived from proopiomelanocortin as well as the neurohypophyseal hormones exert important and substantial effects on brain functions after intracerebroventricular and peripheral administration. This led us to study the effects of intravenous hCRH on brain functions in humans using electroencephalographic techniques. In our experience the event-related potentials (e.g. auditory evoked potentials) provide a sensitive and accurate assay systems to study such effects of peptides. Male volunteers were tested in a dichotic listening paradigm, providing electrophysiological measures of selective attention. Human CRH (50 micrograms/hr i.v.) augmented selective attention as indicated by an increased difference between evoked potential waveforms to attended and to unattended stimuli. The opposite results, a decrease in selective attention, was observed after treatment with the behavioral active fragment of adrenocorticotropin, ACTH 4-10. In comparison to ACTH 4-10, lysine-vasopressin, and cortisol, CRH displayed a unique pattern of influences on event related potentials. From these results we conclude that CRH can affect brain function in man and does so by a direct action on the brain and not only by stimulating the release of other behavioral active hormones.